Intercalary heterochromatin in polytene chromosomes of Drosophila melanogaster

Belyaeva, E. S.; Andreyeva, Evgeniya N.; Belyakin, Stepan N.; Volkova, E. I.; Жимулев, И. Ф.

doi:10.1007/s00412-008-0163-7

Cited by 35 publications

(33 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Heterochromatin is also associated with a number of repressive covalent modifications of histone tails (Grewal and Elgin, 2007). At least two mechanisms are responsible for the highly compact state of heterochromatin: pericentric heterochromatin is dependent on heterochromatin protein 1 (HP1) (Eissenberg and Elgin, 2000) and intercalary heterochromatin is dependent on the polycomb group (PcG) of proteins (Belyaeva et al, 2008;Zhimulev and Belyaeva, 2003). HP1 and Pc recognize their respective target sites with discriminating specificities.…”

Section: Introductionmentioning

confidence: 99%

DrosophilaCAF-1 regulates HP1-mediated epigenetic silencing and pericentric heterochromatin stability

Huang

Zhang

et al. 2010

Journal of Cell Science

View full text Add to dashboard Cite

SummaryChromatin assembly factor 1 (CAF-1) was initially characterized as a histone deliverer in the process of DNA-replication-coupled chromatin assembly in eukaryotic cells. Here, we report that CAF-1 p180, the largest subunit of Drosophila CAF-1, participates in the process of heterochromatin formation and functions to maintain pericentric heterochromatin stability. We provide evidence that Drosophila CAF-1 p180 plays a role in both classes of position effect variegation (PEV) and in the expression of heterochromatic genes. A decrease in the expression of Drosophila CAF-1 p180 leads to a decrease in both H3K9 methylation at pericentric heterochromatin regions and the recruitment of heterochromatin protein 1 (HP1) to the chromocenter of the polytene chromosomes. The artificial targeting of HP1 to a euchromatin location leads to the enrichment of Drosophila CAF-1 p180 at this ectopic heterochromatin, suggesting the mutual recruitment of HP1 and CAF-1 p180. We also show that the spreading of heterochromatin is compromised in flies that have reduced CAF-1 p180. Furthermore, reduced CAF-1 p180 causes a defect in the dynamics of heterochromatic markers in early Drosophila embryos. Together, these findings suggest that Drosophila CAF-1 p180 is an essential factor in the epigenetic control of heterochromatin formation and/or maintenance.

show abstract

Section: Introductionmentioning

confidence: 99%

DrosophilaCAF-1 regulates HP1-mediated epigenetic silencing and pericentric heterochromatin stability

Huang

Zhang

et al. 2010

Journal of Cell Science

View full text Add to dashboard Cite

show abstract

“…There are previously described regions of intercalary heterochromatin in all D. melanogaster euchromatic arms (Belyaeva et al 2008) that could be responsible for the H3K9me2-enriched domains found in all cell types and tissues. Comparing regions of intercalary heterochromatin with the positions of the H3K9me2-enriched domains, we find that only one of 23 regions coincide with intercalary heterochromatin identified by polytene chromosome analysis (Semeshin et al 2001), and six of 23 regions overlap with intercalary heterochromatin defined by ChIP-chip mapping of the SUUR protein (Belyakin et al 2005).…”

Section: The 4th Chromosome Is Enriched For Specialized Heterochromatmentioning

confidence: 99%

Plasticity in patterns of histone modifications and chromosomal proteins in Drosophila heterochromatin

Riddle¹,

Minoda²,

Kharchenko³

et al. 2010

Genome Res.

254

317

View full text Add to dashboard Cite

Eukaryotic genomes are packaged in two basic forms, euchromatin and heterochromatin. We have examined the composition and organization of Drosophila melanogaster heterochromatin in different cell types using ChIP-array analysis of histone modifications and chromosomal proteins. As anticipated, the pericentric heterochromatin and chromosome 4 are on average enriched for the “silencing” marks H3K9me2, H3K9me3, HP1a, and SU(VAR)3-9, and are generally depleted for marks associated with active transcription. The locations of the euchromatin–heterochromatin borders identified by these marks are similar in animal tissues and most cell lines, although the amount of heterochromatin is variable in some cell lines. Combinatorial analysis of chromatin patterns reveals distinct profiles for euchromatin, pericentric heterochromatin, and the 4th chromosome. Both silent and active protein-coding genes in heterochromatin display complex patterns of chromosomal proteins and histone modifications; a majority of the active genes exhibit both “activation” marks (e.g., H3K4me3 and H3K36me3) and “silencing” marks (e.g., H3K9me2 and HP1a). The hallmark of active genes in heterochromatic domains appears to be a loss of H3K9 methylation at the transcription start site. We also observe complex epigenomic profiles of intergenic regions, repeated transposable element (TE) sequences, and genes in the heterochromatic extensions. An unexpectedly large fraction of sequences in the euchromatic chromosome arms exhibits a heterochromatic chromatin signature, which differs in size, position, and impact on gene expression among cell types. We conclude that patterns of heterochromatin/euchromatin packaging show greater complexity and plasticity than anticipated. This comprehensive analysis provides a foundation for future studies of gene activity and chromosomal functions that are influenced by or dependent upon heterochromatin.

show abstract

“…In the best-studied system, the Drosophila larval salivary gland (Fig. 1A), late-replicating euchromatic regions (''intercalary heterochromatin'') also underreplicate to varying degrees (for review, see Spradling and OrrWeaver 1987;Belyaeva et al 2008). Thirty to 52 underreplicated (UR) regions 90-570 kb in length have been precisely mapped using DNA arrays (Belyakin et al 2005;Nordman et al 2011;Sher et al 2012).…”

mentioning

confidence: 99%

Incomplete replication generates somatic DNA alterations within Drosophila polytene salivary gland cells

2014

View full text Add to dashboard Cite

DNA replication remains unfinished in many Drosophila polyploid cells, which harbor disproportionately fewer copies of late-replicating chromosomal regions. By analyzing paired-end high-throughput sequence data from polytene larval salivary gland cells, we define 112 underreplicated (UR) euchromatic regions 60-480 kb in size. To determine the effects of underreplication on genome integrity, we analyzed anomalous read pairs and breakpoint reads throughout the euchromatic genome. Each UR euchromatic region contains many different deletions 10-500 kb in size, while very few deletions are present in fully replicated chromosome regions or UR zones from embryo DNA. Thus, during endocycles, stalled forks within UR regions break and undergo local repair instead of remaining stable and generating nested forks. As a result, each salivary gland cell contains hundreds of unique deletions that account for their copy number reductions. Similar UR regions and deletions were observed in ovarian DNA, suggesting that incomplete replication, fork breakage, and repair occur widely in polytene cells. UR regions are enriched in genes encoding immunoglobulin superfamily proteins and contain many neurally expressed and homeotic genes. We suggest that the extensive somatic DNA instability described here underlies position effect variegation, molds the structure of polytene chromosomes, and should be investigated for possible functions.

show abstract

Intercalary heterochromatin in polytene chromosomes of Drosophila melanogaster

Cited by 35 publications

References 54 publications

DrosophilaCAF-1 regulates HP1-mediated epigenetic silencing and pericentric heterochromatin stability

DrosophilaCAF-1 regulates HP1-mediated epigenetic silencing and pericentric heterochromatin stability

Plasticity in patterns of histone modifications and chromosomal proteins in Drosophila heterochromatin

Incomplete replication generates somatic DNA alterations within Drosophila polytene salivary gland cells

Contact Info

Product

Resources

About